Bicycle suspension systems have become increasingly popular. Suspension systems for both the front and rear wheels of bicycles are employed with increasing frequency particularly in off-road or "mountain" bicycle designs to enhance rider comfort when traveling over rough terrain.
A significant disadvantage of many prior art bicycle suspension systems is that their designs dictated a trade-off between comfort of ride over rough terrain and pedaling efficiency. Most bicycle suspensions, according to the prior art, are designed to absorb forces directed substantially perpendicularly relative to the ground. However, during hard pedaling, a rider exerts substantial forces in a downwardly directed direction. Thus, if the suspension's springs are aligned to absorb, primarily, perpendicularly-directed forces, then they also respond to downwardly-directed pedaling forces. A soft spring may provide maximum cushioning when traversing rough obstacles, but it will also cause the bicycle to bounce or "pogo", periodically, as the rider pedals. This bounce reduces controllability and wastes pedaling energy, making the bicycle less efficient and increasing rider fatigue. The only way to avoid pedal-induced-bounce in such prior art suspension systems is to increase the stiffness of the suspension springs. By increasing spring stiffness, however, the suspension system loses much of its cushioning effect when traversing rough terrain.
Applicant's U.S. Pat. No. 5,217,241, which is expressly incorporated herein by reference, discloses a bicycle suspension system that is particularly applicable to the rear wheel and that eliminates much of the trade-off between smooth ride and pedal, efficiency. By orienting the suspension elements so that deflection of the suspension system is more sensitive to terrain-induced impacts at times in which rough terrain is likely to be negotiated, and less sensitive to such impacts at times when hard pedaling is likely to occur, the need to trade ride comfort for efficiency is largely eliminated.
In view of the disadvantages of the prior art, it is therefore, an object of this invention to provide a bicycle suspension system for use with the front fork of a bicycle that reduces the need o trade riding comfort for pedaling efficiency. The suspension system according to this invention should be adjustable in view of differing ride requirements and should be durable, relatively easily constructed and safe to use.